VServer 1.9.2 (patch-2.6.8.1-vs1.9.2.diff)

[linux-2.6.git] / arch / i386 / mm / init.c

diff --git a/arch/i386/mm/init.c b/arch/i386/mm/init.c
index 19ba96e..a8bd054 100644 (file)
--- a/arch/i386/mm/init.c
+++ b/arch/i386/mm/init.c
@@ -32,7 +32,6 @@
 #include <asm/system.h>
 #include <asm/uaccess.h>
 #include <asm/pgtable.h>
-#include <asm/pgalloc.h>
 #include <asm/dma.h>
 #include <asm/fixmap.h>
 #include <asm/e820.h>
@@ -123,6 +122,13 @@ static void __init page_table_range_init (unsigned long start, unsigned long end
        }
 }
 
+static inline int is_kernel_text(unsigned long addr)
+{
+       if (addr >= (unsigned long)_stext && addr <= (unsigned long)__init_end)
+               return 1;
+       return 0;
+}
+
 /*
  * This maps the physical memory to kernel virtual address space, a total 
  * of max_low_pfn pages, by creating page tables starting from address 
@@ -145,18 +151,29 @@ static void __init kernel_physical_mapping_init(pgd_t *pgd_base)
                if (pfn >= max_low_pfn)
                        continue;
                for (pmd_idx = 0; pmd_idx < PTRS_PER_PMD && pfn < max_low_pfn; pmd++, pmd_idx++) {
+                       unsigned int address = pfn * PAGE_SIZE + PAGE_OFFSET;
+
                        /* Map with big pages if possible, otherwise create normal page tables. */
                        if (cpu_has_pse) {
-                               set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE));
+                               unsigned int address2 = (pfn + PTRS_PER_PTE - 1) * PAGE_SIZE + PAGE_OFFSET + PAGE_SIZE-1;
+
+                               if (is_kernel_text(address) || is_kernel_text(address2))
+                                       set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE_EXEC));
+                               else
+                                       set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE));
                                pfn += PTRS_PER_PTE;
                        } else {
                                pte = one_page_table_init(pmd);
 
-                               for (pte_ofs = 0; pte_ofs < PTRS_PER_PTE && pfn < max_low_pfn; pte++, pfn++, pte_ofs++)
-                                       set_pte(pte, pfn_pte(pfn, PAGE_KERNEL));
+                               for (pte_ofs = 0; pte_ofs < PTRS_PER_PTE && pfn < max_low_pfn; pte++, pfn++, pte_ofs++) {
+                                               if (is_kernel_text(address))
+                                                       set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC));
+                                               else
+                                                       set_pte(pte, pfn_pte(pfn, PAGE_KERNEL));
+                               }
                        }
                }
-       }       
+       }
 }
 
 static inline int page_kills_ppro(unsigned long pagenr)
@@ -273,7 +290,8 @@ extern void set_highmem_pages_init(int);
 #define set_highmem_pages_init(bad_ppro) do { } while (0)
 #endif /* CONFIG_HIGHMEM */
 
-unsigned long __PAGE_KERNEL = _PAGE_KERNEL;
+unsigned long long __PAGE_KERNEL = _PAGE_KERNEL;
+unsigned long long __PAGE_KERNEL_EXEC = _PAGE_KERNEL_EXEC;
 
 #ifndef CONFIG_DISCONTIGMEM
 #define remap_numa_kva() do {} while (0)
@@ -302,6 +320,7 @@ static void __init pagetable_init (void)
        if (cpu_has_pge) {
                set_in_cr4(X86_CR4_PGE);
                __PAGE_KERNEL |= _PAGE_GLOBAL;
+               __PAGE_KERNEL_EXEC |= _PAGE_GLOBAL;
        }
 
        kernel_physical_mapping_init(pgd_base);
@@ -392,6 +411,79 @@ void __init zone_sizes_init(void)
 extern void zone_sizes_init(void);
 #endif /* !CONFIG_DISCONTIGMEM */
 
+static int disable_nx __initdata = 0;
+u64 __supported_pte_mask = ~_PAGE_NX;
+
+/*
+ * noexec = on|off
+ *
+ * Control non executable mappings.
+ *
+ * on      Enable
+ * off     Disable
+ */
+static int __init noexec_setup(char *str)
+{
+       if (!strncmp(str, "on",2) && cpu_has_nx) {
+               __supported_pte_mask |= _PAGE_NX;
+               disable_nx = 0;
+       } else if (!strncmp(str,"off",3)) {
+               disable_nx = 1;
+               __supported_pte_mask &= ~_PAGE_NX;
+       }
+       return 1;
+}
+
+__setup("noexec=", noexec_setup);
+
+#ifdef CONFIG_X86_PAE
+int nx_enabled = 0;
+
+static void __init set_nx(void)
+{
+       unsigned int v[4], l, h;
+
+       if (cpu_has_pae && (cpuid_eax(0x80000000) > 0x80000001)) {
+               cpuid(0x80000001, &v[0], &v[1], &v[2], &v[3]);
+               if ((v[3] & (1 << 20)) && !disable_nx) {
+                       rdmsr(MSR_EFER, l, h);
+                       l |= EFER_NX;
+                       wrmsr(MSR_EFER, l, h);
+                       nx_enabled = 1;
+                       __supported_pte_mask |= _PAGE_NX;
+               }
+       }
+}
+
+/*
+ * Enables/disables executability of a given kernel page and
+ * returns the previous setting.
+ */
+int __init set_kernel_exec(unsigned long vaddr, int enable)
+{
+       pte_t *pte;
+       int ret = 1;
+
+       if (!nx_enabled)
+               goto out;
+
+       pte = lookup_address(vaddr);
+       BUG_ON(!pte);
+
+       if (!pte_exec_kernel(*pte))
+               ret = 0;
+
+       if (enable)
+               pte->pte_high &= ~(1 << (_PAGE_BIT_NX - 32));
+       else
+               pte->pte_high |= 1 << (_PAGE_BIT_NX - 32);
+       __flush_tlb_all();
+out:
+       return ret;
+}
+
+#endif
+
 /*
  * paging_init() sets up the page tables - note that the first 8MB are
  * already mapped by head.S.
@@ -401,6 +493,12 @@ extern void zone_sizes_init(void);
  */
 void __init paging_init(void)
 {
+#ifdef CONFIG_X86_PAE
+       set_nx();
+       if (nx_enabled)
+               printk("NX (Execute Disable) protection: active\n");
+#endif
+
        pagetable_init();
 
        load_cr3(swapper_pg_dir);